Converter for use in the metallurgical treatment of iron



Q United States Patent n113,540,712 [72] lnventors Leonhard llohle [56] References Cited I H UNITED STATES PATENTS ggzzz 3,430,941 3/l969 Lambrechtetal 266/36 211 Appl. No. 103,352 FOREIGN PATENTS [22] Filed Fh.6, 1968 1,355,699 2/1964 France 266/36(P) 4s Patented Nov. 11, 1910 P E d Fr [73] Assignee Gesellschnit fur Huttenwerksanlagen 3223 gfxgfg fig b 3:2 :8 Germany AttorneyCurt M. Avery, Arthur E. Wilfond, Herbert L. a d Priority Feb. 9,1967 Lerner an Daniel] Trek [33] Germany N0-G49203 ABSTRACT: This invention is concerned with providing an [54] CONVERTER FOR USE IN THE METALLURGICAL [50] Field of Search 266/36 C2lc 5/42 266/35,

iron converter having a capacity of the order of 100 tons with a mounting by which the converter vessel can be gyrated about an axis offset from its own axis, without rotating about its own axis at the same time, while a refining process is in progress. This motion generates a wave in the melt which facilitates mixing and hence speeds the refining. The converter vessel is mounted in an eccentric ring so that the eccentric ring is rotatable about the vessel, and the eccentric ring in turn is rotatably mounted within a fixed carrier ring. There is a drive for rotating the eccentric ring about its own axis and by this rotation, the converter vessel is caused to gyrate about the eccentric axis while not rotating about its own axis.

CONVERTER FOR USE IN THE METALLURGICAL TREATMENT OF IRON The invention relates to converters for use in the metallurgical treatment of iron, particularly the refining of crude iron by the oxygen-blowing process.

Converters known as shaker ladies are already known and are mounted in a pivoting mechanism which causes the converter to carry out a circular motion without actually rotating about its own axis. Above a critical rotation speed, a wave forms on the surface of a melt situated in the shaker ladle, leading to a very good mixing and thus to an acceleration of the reactions which take place in the melt. As a result of the good mixing of the melt, a rapid desulphurisation and denitrogenation are obtained, and thus an iron of high quality is formed.

Apart from the use of the shaker ladle for the treatment of cast iron, refiningexperiments have also been carried out in shaker ladies with a capacity of about 5 to 7 tons, in which oxygen was blown on to the bath, which was in vigorous motion. it was ascertained that as a result of the better bath mixing, in comparison with the ordinary blowing process, a more rapid decarbonisation and an oxidation of the phosphorous, silicon and other accompanying elements of the crude iron before decarbonisation, and a better desulphurisation by combustion of a part of the sulphur ofthc slag into S0 are obtained. The better metallurgical effect of the oxygen-blowing process in the shaker ladle is caused, apart from the better bath mixing, by the fact that the refining reactions take place with relatively low blowing pressure, not byway of the so-calied focal spot method but indirectly-by way of the slag covering method. Finally the steel refined by the blowing-on, of oxygen in a shaker ladle possesses'a lower nitrogen content than steel refined in a stationary converter.

The application of the knowledge obtained in experimental smelting in shaker ladies with small capacity to large industrial production of steel in vessels having a capacity, for example,

of 100 tons failed .hitherto because the known pivoting mechanisms are not suitable for the movement of such large units. The conventional shaker ladies are in fact mountedin a horseshoe-shaped or triangular pivot frame, which is carried by supports at three points. A crank of specific eccentricity, driven by an electric motor, is mounted in each of the supports. in the case of three cranks arranged at the angles of an equilateral triangle a uniform crank loading is obtained, the upper limit of which lies between 70 and 80 tons per crank. This corresponds to a maximum ladle content of 30 tons. Shaker ladies with a capacity of 30 tons, however, require such expensive special bearings that their use is not economically tolerable. if, on the other hand, more than three cranks are used, then special measures must be taken to ensure uniform loading, made particularly difficult by the different warming and thermal expansion of the parts of the apparatus which is caused by the liquid melt, so that jamming between the cranks can easily occur.

Also, a centrifugal ladle has been proposed, which is mounted at three points in an obliquely placed centrifuge framework. The tip of the conically downwardly tapering centrifuge frameworkis provided with a drive so that the centrifuge framework can roll on a fixed roilway of somewhat larger diameter, with point contact, by means of a circular rolling track. To generate a bath wave the ladle together with the centrifuge framework carries out a rotation about its central axis; and is therefore different from the shaker ladle methods described earlier, in which the bath wave .is generated without rotation of the ladle about its own axis.

A converter is also known in which the known oxygen blowing process can be carried out in the vertical position and the similarly known Kaldo" process can be carried out inan oblique position. in this case the converter is mounted in a race which is supported in a carrier ring by radial and axial rollers which are arranged in pairs on rocking levers. The radial rollers are driven'to rotate the converter about its longitudinal axis.

The apparatus known for the execution of the combination process is however very expensive, if only on account of the separate oxygen supply the waste gas cleansing and the introduction'of the additives in the two operational positions (LD- and Kaldo positions). Furthermore it is not suitable to impart to the bath a movement corresponding to that used in the shaker ladle process. 7

Now, with the aim of providing a converter, having a capacity of for example tons, in which crude iron can be refined by the oxygen blowing process and which is given the shaker ladle movement during the refining, according to the invention, the converter is mounted in an eccentric ring which is in turn mounted rotatably within a carrier ring, the eccentric ring beingrotatable on the converter and there being means for rotating the eccentric ring about its own eccentric axis so that the converter is caused to gyrate about the axis of the eccentric ring, but not to rotate about its own axis. As explained earlier, this shakes up the melt in the converter so that extremely good mixing isobtained and hence the refining is speeded up.

Preferably the converter is carried by a mounting ring which is surrounded by the'eccentric ring. and the eccentric ring carrying inner rollers which ride on a track on the outer face of the mounting ring and outer rollers which ride on a track on the inner face of the carrier ring. These rollers may be mountedjn pairs, the rollers of each pair being mounted at the ends of a rocking leverwhich is pivoted about its centre on the eccentric ring.

Preferably the eccentric ring has on its under surface a circular track which is coaxial with the axis of the eccentric ring, and this track bears on a setof lower support rollers which are mounted on the carrier ring. Also, the mounting ring preferabiycarriesa set of upper support rollers, these rollers riding-on a circulartraclcon the upper surface of theeccentric ring and this track being coaxial with the axis of the converter. In this case the carrier ring and the mounting ring may carry upper and lowerretaining rollers respectively. The upper retaining rollers engage a track on the-upper surface of the eccentric ring which is similar to that on the under surface on which the lower support rollers ride, and the lower retaining rollers engage a track on the under surface of the eccentric ring which is similar to that on the upper surface on which the upper support rollers ride. These retaining rollers help to keep the various rings steady relative to each other when the converter is tilted, and .are only subject to static stress since the converter is alwaysat rest whentiited.

An example of a converter in accordance with the present invention is. illustrated in the accompanying drawings, in

which:

FIG. 1 is a longitudinal section through the converter; and,

FIG. 2, in the upper half, is a transverse section through the converter along the line H, and, in the lower half, is a transverse section through the converter along the line ll-ll in FIG. 1.

The drawings show a converter 3 and a carrier ring 4, between which'lies-an eccentric ring 5 which is equipped with a toothed rim ,6.in which the pinion of a rotation drive 7 engages.As a result of the eccentricity e of the eccentric ring 5 withrespect to the converter, when the ring 5 is rotated by the drive 7, the axis B of the converter is caused to travel in a circular path C about the axis A of the ring 5 in a manner that will be described later. in order to prevent rotation of the converter itself about its longitudinal axis during this circulation, an articulated support 8 extends from the converter 3, through a mounting ring 13 therefor and a frame for a roller 23 secured to the rings 3 to the carrier ring 4. The carrier ring 4 possesses two journals 9 and 11, which are seated in bearings of the kind usually used in converters. in the upright position, that is in the refining position, the converter 3 is locked by a locking device 12.

The converter 3 is supported in the mounting ring 13, which has on its outer face a circumferential track 14 against which bear inner radial rollers 15 which are carried by the eccentric ring 5. The eccentric ring 5 also carries outer radial rollers 16 which bear upon a track 17 on the inner face of the carrier ring 4. The radial rollers 15, 16 are mounted in pairs -on rocking levers 18, 19 respectively, and serve to take up the centrifugal force occurring during the circulation of the converter 3 and acting in the direction of the eccentric radius. This means that the centrifugal forces of the converter 3 are transmitted through the rollers to the rotating eccentric ring 5 and then through the radial rollers 16 to the carrier ring 4. Further radial rollers 21. 22 serve to support and stabilize the rotating eccentric ring 5, but are not subject to the action of centrifugal force. The radial rollers 15, 16 are offset slightly in relation to one another. and therefore the eccentric ring Sis stressed only in a relatively small region under the action of the centrifugal force.

in order to keep the weight, and thus the inertia moment of the eccentric ring 5 as small as possible, the support rollers 23. for axially supporting the converter 3 in the ring 5 are mounted on the converter 3, and the support rollers 24 for axially supporting the ring 5 in the ring 4 are mounted on the carrier ring 4 while theeccentric ring 5 carries only the corresponding tracks. In this case, the uppersupport rollers 23 are secured to the mounting ring 13 and the lower support rollers 24 to the carrier ring 4, while upper retaining rollers 25 are secured to the carrier ring 4 and lower retaining rollers 26 to the mounting ring 13. These retaining rollers 25, 26 engages tracks on the eccentric ring 5 and serve to hold the converter 3 and the eccentric ring 5 fast when the converter 3 is tilted.

The retaining rollers 25, 26 are subjected only to static stress in tilting, sincethe converter 3 is at rest during tilting, while the support rollers 23, 24 are also subjected to dynamic stress during the circulating movement of the converter and the rotation ofthe eccentric ring 5. For this reason, with equal roller size the number of the retaining rollers 25, 26 is substantially smaller than the number of the support rollers 23,24. A particularly compact construction style is obtained if the retaining rollers 26 each lie in a gap between two support rollers 23, 24. In order to achieve good rolling conditions with linear contacts, the radial rollers l5, 16, 21, 22 are formed as cylindrical rollers while the support and retaining rollers 23, 24, 25, 26 are formed as taper rollers, and all the rollers are elastically mounted in order to ensure smooth running.

in order to keep the thermal expansion of the converter 3 remote from the rollers and tracks, the converter 3 is fitted to the mounting ring 13 by means of brackets 27, only two of which form a rigid connection, these two being off set in relation to one another by about 90. On the other hand, the other brackets 27 are fitted to the mounting ring 13 to that radial movement is allowed. An annular cover 28 protects the mountings of the converter 3 and the eccentric ring 5 against dust and converter discharge.

If as a result of thermal expansion the centre of the converter 3 shifts, this has no influence upon the magnitude of the centrifugal force generated, since this is determined solely by the radius ofthe eccentric ring 5. Antifriction bearings of ordinary design and size are used for the individual rollers. For a 100 ton converter in accordance with the invention, although the rotation speed of the eccentric ring 5 amounts to about 35 rpm, in the case of a toothed rim diameter of about l0 metres, a peripheral speed of nearly 20 metresper second is obtained.

We claim:

1. A converter for use in the metallurgical treatment of iron including a converter vessel, an eccentric ring surrounding said converter vessel, means mounting said converter vessel in said eccentric ring so that said eccentric ring is rotatable about said converter vessel, a carrier ring, means rotatably mounting said eccentric ring within said carrier ring, and means for rotating said eccentric ring about its own eccentric axis so that as said eccentric ring rotates, said converter vessel is caused to gyrate about the axis of said eccentric ring, but not to rotate about its own axis. 7 I

2. A converter as claimed in claim 1, wherein said means mounting said converter-vessel in said eccentric ring includes a mounting ring surrounding said converter vessel and within said eccentric ring, means fixing said converter vessel in said mounting ring, means on the outer face of said mounting ring defining an inner roller track, inner rollers for riding on said inner roller track, and means mounting said inner rollers on said eccentric ring, and whereinsaid means rotatably mounting said eccentric ring with said carrier ring includes means on the inner face of said carrier ring defining an outer roller track, outer rollers for riding on said outer roller track, and means mounting said outer rollers on said eccentric ring.

3. A converter as claimed in claim 2, wherein said inner rollers and said outer rollers are mounted in pairs, each of said pairs of rollers including a rocking lever, means mounting the rollers at the ends of said rocking lever, and means pivoting said rocking lever about its centre on said eccentric ring.

4. A converter as claimed in claim 2, wherein said means rotatably mounting said eccentric ring within said carrier ring further includes means on the under surface of said eccentric ring defining a circular roller track which is coaxial with the axis of said eccentric ring, a set oflower support rollers for riding on said roller track, and means mounting said lower support rollers on said carrier ring.

5. A converter as claimed in claim 4, wherein said means mounting said converter vessel in said eccentric ring further includes means on the upper surface of said eccentric ring defining a circular roller track which is coaxial with the axis of said converter vessel, a set of upper support rollers for riding on said roller track, and means mounting saidupper support rollers on said mounting ring.

6. A converter as 'c'laimedvin claim 5, further comprising upper and lower retaining rollers, means mounting said upper retaining rollers on said carrier ring and means mounting said lower retaining rollers on said mounting ring, means on the upper surface of said eccentric ring defining a roller track for engaging said upper retaining rollers, said roller track being similar to the lower support roller track on the under surface of said eccentric ring, and means on said under surface of said eccentric ring defining a roller track for engaging said lower retaining rollers, said roller track being similar to the upper support roller track on the upper surface of said eccentric ring.

7. A converter asv claimed in claim 6, wherein the support and retaining rollers are taper rollers and said inner and outer rollers are cylindrical rollers.

8. A converter as claimed in claim 6, wherein said means fixing said converter vessel in said mounting ring includes both 'loose and fixed brackets whereby radial expansion of said converter vessel is absorbed.

9. A converter as claimed in claim 6, further comprising an articulated arm, means fixing one end of said articulated arm to saidmounting ring and means fixing the other end of said articulated arm to said carrier ring, whereby it is ensured that said converter vessel does not rotate about its own axis as it gyrates. 

